It is common for tools used in manufacturing processes to have adjustable settings which affect parameters of articles produced by the manufacturing processes. It is further common for a manufacturing process to use a set of one or more tools to perform a particular fabrication step, each tool in the set being capable of performing the fabrication step, to provide a desired level of capacity for the manufacturing process. Moreover, it is common for more than one model of article to be produced by such a manufacturing process in which instances of each model are processed through more than one tool in the set, and in which each tool in the set processes instances of more than one model. Adjusting the settings of the tools to produce the articles with parameters close to desired values may be problematic when models have different desired parameter values and/or performances of the tools drift.